U.S. patent application number 10/192705 was filed with the patent office on 2003-01-16 for optical repeating system and optical amplifying repeater control method.
This patent application is currently assigned to MITSUBISHI DENKI KABUSHIKI KAISHA. Invention is credited to Goto, Hideki, Horiuchi, Yukio, Ishii, Daishi, Kasahara, Yasunori, Kawazawa, Toshio, Mizuochi, Takashi, Shimomura, Kenkichi, Suzuki, Masatoshi.
Application Number | 20030011857 10/192705 |
Document ID | / |
Family ID | 19046553 |
Filed Date | 2003-01-16 |
United States Patent
Application |
20030011857 |
Kind Code |
A1 |
Kasahara, Yasunori ; et
al. |
January 16, 2003 |
Optical repeating system and optical amplifying repeater control
method
Abstract
An optical repeating system includes an optical transmitter and
an optical amplifying repeater. The optical transmitter transmits a
supervisory command and a control command to the optical amplifying
repeater as a first sub-signal. The supervisory command is a
command to supervise internal circuits of the optical amplifying
repeater, and the control command is a command to control the
optical amplifying repeater. The optical amplifying repeater
includes multiple sub-modules each for amplifying and repeating
main signals on multiple sets of optical transmission lines. When
receiving the supervisory command via the optical transmission
line, each sub-module transmits a supervisory signal indicating the
supervisory result associated with the supervisory command to an
optical receiver as a second sub-signal. In addition, when
receiving a predetermined control command via the optical
transmission line, each sub-module initializes another sub-module
of the multiple sub-modules in response to the predetermined
control command. The optical amplifying repeater can restart its
control program even when it has fallen into a state where it is
difficult to continue to execute the normal operation in accordance
with the control program because of some exception or the like.
Inventors: |
Kasahara, Yasunori; (Tokyo,
JP) ; Goto, Hideki; (Tokyo, JP) ; Mizuochi,
Takashi; (Tokyo, JP) ; Shimomura, Kenkichi;
(Tokyo, JP) ; Suzuki, Masatoshi; (Saitama, JP)
; Horiuchi, Yukio; (Saitama, JP) ; Ishii,
Daishi; (Tokyo, JP) ; Kawazawa, Toshio;
(Tokyo, JP) |
Correspondence
Address: |
OBLON SPIVAK MCCLELLAND MAIER & NEUSTADT PC
FOURTH FLOOR
1755 JEFFERSON DAVIS HIGHWAY
ARLINGTON
VA
22202
US
|
Assignee: |
MITSUBISHI DENKI KABUSHIKI
KAISHA
Tokyo
JP
|
Family ID: |
19046553 |
Appl. No.: |
10/192705 |
Filed: |
July 11, 2002 |
Current U.S.
Class: |
398/178 |
Current CPC
Class: |
H04B 10/298 20200501;
H04B 2210/074 20130101; H04B 10/0777 20130101 |
Class at
Publication: |
359/179 ;
359/174 |
International
Class: |
H04B 010/02; H04B
010/16 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 11, 2001 |
JP |
2001-211199 |
Claims
What is claimed is:
1. An optical repeating system comprising: multiple sets of optical
transmission lines; an optical transmitter and an optical receiver
for transmitting and receiving main signals via said multiple sets
of optical transmission lines; and an optical amplifying repeater
installed at an intermediate position on said multiple sets of
optical transmission lines for amplifying and repeating the main
signals with optical amplifiers, wherein said optical transmitter
transmits a first sub-signal containing at least one of a
supervisory command and a control command to said optical
amplifying repeater, the supervisory command commanding to
supervise internal circuits of said optical amplifying repeater,
and the control command commanding to control said optical
amplifying repeater, wherein said optical amplifying repeater
includes a multiple sub-modules for amplifying and repeating the
main signals on said multiple sets of optical transmission lines,
and wherein each of said sub-modules transmits, when receiving the
supervisory command via one of said optical transmission lines, a
second sub-signal containing a supervisory signal indicating a
supervisory result corresponding to the supervisory command to said
optical receiver, and initializes, when receiving a predetermined
control command via one of said optical transmission lines, another
sub-module of said multiple sub-modules in response to the
predetermined control command.
2. The optical repeating system according to claim 1, wherein each
of said sub-modules executes processing corresponding to the
supervisory command and the control command in accordance with a
prescribed control program, and restarts, when receiving the
predetermined control command, the another sub-module of said
multiple sub-modules in response to the predetermined control
command.
3. The optical repeating system according to claim 1, wherein said
multiple sets of optical transmission lines each consist of a pair
of uplink and downlink bidirectional optical transmission lines,
and wherein each of said multiple sub-modules amplifies and repeats
the main signals on said uplink and downlink optical transmission
lines, receives the first sub-signal via said uplink or downlink
optical transmission line, and transmits the second sub-signal via
said uplink and downlink optical transmission lines.
4. The optical repeating system according to claim 1, wherein each
of said sub-modules executes self-diagnosis in accordance with a
self-diagnosis program, supplies its self-diagnosis result to the
another sub-module of said multiple sub-modules, and transmits a
self-diagnosis result from the another sub-module of said multiple
sub-modules to said optical receiver.
5. The optical repeating system according to claim 2, wherein each
of said sub-modules updates data and control program of the another
sub-module of said multiple sub-modules.
6. An optical amplifying repeater control method of controlling an
optical amplifying repeater in an optical repeating system
including multiple sets of optical transmission lines, an optical
transmitter and an optical receiver for transmitting and receiving
main signals via said multiple sets of optical transmission lines,
and an optical amplifying repeater installed at an intermediate
position on said multiple sets of optical transmission lines for
amplifying and repeating the main signals with optical amplifiers,
said optical amplifying repeater control method comprising the
steps of: transmitting a first sub-signal containing at least one
of a supervisory command and a control command to said optical
amplifying repeater by said optical transmitter, the supervisory
command commanding to supervise internal circuits of said optical
amplifying repeater, and the control command commanding to control
said optical amplifying repeater; receiving at least one of the
supervisory command and the control command by one of multiple
sub-modules in said optical amplifying repeater via said multiple
sets of optical transmission lines, said multiple sub-modules
amplifying and repeating the main signals on said multiple sets of
optical transmission lines; and transmitting a second sub-signal
that contains a supervisory signal indicating supervisory result
corresponding to the supervisory command from said one of multiple
sub-modules to said optical receiver when said one of multiple
sub-modules receives the supervisory command, and initializing,
when said one of multiple sub-modules receives a predetermined
control command, another sub-module of said multiple sub-modules in
response to the predetermined control command.
7. An optical amplifying repeater control method of controlling an
optical amplifying repeater in an optical repeating system
including multiple sets of optical transmission lines, an optical
transmitter and an optical receiver for transmitting and receiving
main signals via said multiple sets of optical transmission lines,
and an optical amplifying repeater installed at an intermediate
position on said multiple sets of optical transmission lines for
amplifying and repeating the main signals with optical amplifiers,
said optical amplifying repeater including multiple sub-modules
each for amplifying and repeating the main signals on said multiple
sets of optical transmission lines, said optical amplifying
repeater control method comprising the steps of: transmitting a
first sub-signal containing at least one of a supervisory command
and a control command from said optical transmitter to said optical
amplifying repeater, the supervisory command commanding to
supervise internal circuits of said optical amplifying repeater,
and the control command commanding to control said optical
amplifying repeater; and transmitting, when one of said multiple
sub-modules receives the supervisory command via said optical
transmission lines, a second sub-signal containing a supervisory
signal indicating supervisory result corresponding to the
supervisory command from said one of said multiple sub-modules to
said optical receiver, and switching, when said one of said
sub-modules receives a predetermined control command via said
optical transmission lines, the optical transmission line for
transmitting the second sub-signal to the transmission line of
another set of said multiple sets of optical transmission lines,
via another sub-module of said multiple sub-modules in response to
the predetermined control command.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an optical repeating system
that comprises multiple sets of optical transmission lines, optical
transmitters and optical receivers for transferring main signals
through each set of optical transmission lines, and optical
amplifying repeaters for amplifying and repeating the main signal
with optical amplifiers at intermediate positions on the multiple
sets of optical transmission lines, and to an optical amplifying
repeater control method for controlling the optical amplifying
repeaters.
[0003] 2. Description of Related Art
[0004] FIG. 4 is a block diagram showing a configuration of a
conventional optical repeating system disclosed in Japanese patent
No. 2,716,882. In FIG. 4, the reference numeral 1 designates an
optical transmitter for transmitting a main signal conveying
information and a first sub-signal bearing a command for an optical
amplifying repeater 3; 2 designates an optical fiber constituting
an optical transmission line for interconnecting the optical
transmitter 1, optical amplifying repeaters 3 and an optical
receiver 4; 3 designates an optical amplifying repeater located at
an intermediate position on the optical fiber 2 for not only
amplifying and transmitting the main signal with an optical
amplifier, but also for superimposing the supervisory information
obtained from the command conveyed by the first sub-signal on the
main signal as a second sub-signal, and 4 designates an optical
receiver for receiving the main signal and the like.
[0005] FIG. 5 is a block diagram showing a configuration of the
optical amplifying repeater as shown in FIG. 4. In the optical
amplifying repeater 3 as shown in FIG. 5, the reference numeral 101
designates a coupler for splitting the input optical signal; 102
designates an optical amplifier comprising an isolator 111, a
pumping laser diode 112, a multiplexing filter 113, an erbium (Er)
doped optical fiber 114, and an isolator 115; and 103 designates a
coupler for splitting an optical signal output from the optical
amplifier 102, and for outputting its first part as the output
optical signal.
[0006] In FIG. 5, the reference numeral 121 designates a
photoelectric converter for converting an optical signal to an
electrical signal; 122 designates an amplifier for amplifying the
electrical signal; 123 designates a low-pass filter for filtering
the sub-signal; 124 designates an incoming call identification
circuit for making a decision as to whether the first sub-signal
contains an operation command signal addressed to the present
repeater; 125 designates a controller for actuating an encoder 131
and a modulator 132 in response to the operation command signal
addressed to the present repeater; 131 designates the encoder for
encoding intra-repeater information such as the power level of the
output optical signal of the optical amplifying repeater 3, the
amplification factor of the optical amplifier 102, the driving
current level and temperature of the pumping laser diode 112; and
132 designates the modulator for modulating the driving current to
be supplied from the pumping laser diode driver 133 to the pumping
laser diode 112 by a supervisory signal including the
intra-repeater information after encoding. The reference numeral
134 designates a temperature controller for controlling the
temperature of the pumping laser diode 112; 141 designates a
photoelectric converter for converting an optical signal to an
electrical signal; and 142 designates an amplifier for amplifying
the electrical signal.
[0007] FIG. 6 is a block diagram showing a configuration of the
optical transmitter 1 in FIG. 4. In the optical transmitter 1 of
FIG. 6, the reference numeral 201 designates a main signal circuit
for outputting the main signal used for information transmission;
202 designates a sub-signal circuit for outputting the first
sub-signal containing the operation command that specifies the
optical amplifying repeater; 203 designates a modulator for
superimposing the first sub-signal on the main signal in a
prescribed modulating scheme; 204 designates a driver supplied with
the main signal on which the first sub-signal is superimposed for
driving a semiconductor laser 205; and 205 designates the
semiconductor laser for supplying the optical fiber 2 with the
optical signal corresponding to the applied electrical signal.
[0008] FIG. 7 is a block diagram showing a configuration of the
optical receiver in FIG. 4. In the optical receiver 4 of FIG. 7,
the reference numeral 301 designates a photoelectric converter for
converting the input optical signal fed from the optical fiber 2 to
an electrical signal; 302 designates an amplifier for amplifying
the electrical signal; 303 designates a main signal demodulator for
demodulating the main signal in the received signal; 304 designates
a low-pass filter for filtering the first and second sub-signals in
the received signal; and 305 designates a sub-signal demodulator
for demodulating the first and second sub-signals in the received
signal.
[0009] Next, the operation of the conventional optical repeating
system will be described.
[0010] First, the operation of the optical transmitter 1 will be
described. The sub-signal circuit 202 generates the first
sub-signal, which includes the operation command specifying one of
the optical amplifying repeaters 3 by an address code uniquely
assigned to each optical amplifying repeater, in such a manner that
its amplitude is smaller and its rate is lower than those of the
main signal output from the main signal circuit 201. Then, the
modulator 203 supplies the driver 204 with the main signal on which
the first sub-signal is superimposed. The output optical signal of
the semiconductor laser 205 consists of the modulation signal of
the main signal plus the first sub-signal superimposed thereon. The
optical transmitter 1 transmits the operation command to the next
optical amplifying repeater 3 as the first sub-signal in such a
manner that an appropriate time interval is reserved after the
first sub-signal including the operation command. The reserved time
interval enables the specified optical amplifying repeater 3 to
transmit a supervisory signal corresponding to the first sub-signal
during the reserved time interval as the second sub-signal.
[0011] Next, the operation of the optical amplifying repeater 3
will be described. The coupler 101 splits the input optical signal
fed from the input side optical fiber 2. A first part of the split
input optical signal is launched into the optical amplifier 102 to
be amplified. On the other hand, a second part of the split input
optical signal is launched into the photoelectric converter 121 to
be converted to the electrical signal. The electrical signal is
amplified by the amplifier 122, and then the low-pass filter 123
extracts the first sub-signal with a frequency lower than the
frequency of the main signal, and supplies it to the incoming call
identification circuit 124. The incoming call identification
circuit 124 makes a decision as to whether the optical transmitter
1 sends the operation command to this repeater from the address
code contained in the first sub-signal, and notifies the controller
125 of the decision result. When the operation command is addressed
to the repeater, the controller 125 actuates the encoder 131 and
the modulator 132 to modulate the driving current to be supplied
from the pumping laser diode driver 133 to the pumping laser diode
112 by the second sub-signal including the intra-repeater
information. Since the driving current to the pumping laser diode
112 is modulated by the second sub-signal, the amplification factor
of the optical amplifier 102 is modulated. Thus, the optical signal
output from the optical amplifier 102 consists of the main signal
and the second sub-signal superimposed thereon. On the other hand,
when there is no operation command addressed to the repeater, the
controller 125 does not actuate the encoder 131 nor the modulator
132. As a result, the pumping laser diode 112 is driven by a
non-modulated driving current.
[0012] Finally, the operation of the optical receiver 4 will be
described. The input optical signal fed from the optical fiber 2 is
converted by the photoelectric converter 301 into an electrical
signal which is amplified by the amplifier 302. The amplified
electrical signal is supplied to the main signal demodulator 303.
In parallel with this, the low-pass filter 304 extracts the first
and second sub-signals from the electrical signal, and supplies
them to the sub-signal demodulator 305. The sub-signal demodulator
305 demodulates the operation command, which is addressed to the
optical amplifying repeater 3, from the first sub-signal
transmitted from the optical transmitter 1, and the intra-repeater
information from the second sub-signal transmitted from the optical
amplifying repeater 3. Thus, the operating state of each optical
amplifying repeater 3 can be supervised.
[0013] In this way, the optical transmitter 1 selects one of the
optical amplifying repeaters 3 one by one, and transmits the
operation command by superimposing it on the main signal. Receiving
the operation command addressed to it, each optical amplifying
repeater 3 superimposes the supervisory information about the
repeater on the main signal, and sends it to the optical receiver
4. The optical receiver 4 demodulates the supervisory information
sent from the optical amplifying repeaters 3 sequentially.
[0014] With the foregoing configuration, the conventional optical
repeating system has a problem in that it difficult for the control
program that controls the optical amplifying repeaters 3 to restart
its normal operation once it has fallen into a trouble where it can
hardly continue its normal processing because of some exception.
For example, once the control program has fallen into a state where
it is difficult to execute any processing in accordance with the
first sub-signal, and/or to execute the receiving processing of
that normally, the control program can scarcely restart the optical
amplifying repeater.
SUMMARY OF THE INVENTION
[0015] The present invention is implemented to solve the foregoing
problem. It is therefore an object of the present invention to
provide an optical repeating system and optical amplifying repeater
control method capable of recovering a sub-module that has fallen
into a trouble to the normal operating state with ease.
[0016] According to a first aspect of the present invention, there
is provided an optical repeating system comprising: multiple sets
of optical transmission lines; an optical transmitter and an
optical receiver for transmitting and receiving main signals via
the multiple sets of optical transmission lines; and an optical
amplifying repeater installed at an intermediate position on the
multiple sets of optical transmission lines for amplifying and
repeating the main signals with optical amplifiers, wherein the
optical transmitter transmits a first sub-signal containing at
least one of a supervisory command and a control command to the
optical amplifying repeater, the supervisory command commanding to
supervise internal circuits of the optical amplifying repeater, and
the control command commanding to control the optical amplifying
repeater, wherein the optical amplifying repeater includes a
multiple sub-modules for amplifying and repeating the main signals
on the multiple sets of optical transmission lines, and wherein
each of the sub-modules transmits, when receiving the supervisory
command via one of the optical transmission lines, a second
sub-signal containing a supervisory signal indicating a supervisory
result corresponding to the supervisory command to the optical
receiver, and initializes, when receiving a predetermined control
command via one of the optical transmission lines, another
sub-module of the multiple sub-modules in response to the
predetermined control command.
[0017] Here, each of the sub-modules may execute processing
corresponding to the supervisory command and the control command in
accordance with a prescribed control program, and restart, when
receiving the predetermined control command, the another sub-module
of the multiple sub-modules in response to the predetermined
control command.
[0018] The multiple sets of optical transmission lines may each
consist of a pair of uplink and downlink bidirectional optical
transmission lines, and each of the multiple sub-modules may
amplify and repeat the main signals on the uplink and downlink
optical transmission lines, receive the first sub-signal via the
uplink or downlink optical transmission line, and transmit the
second sub-signal via the uplink and downlink optical transmission
lines.
[0019] Each of the sub-modules may execute self-diagnosis in
accordance with a self-diagnosis program, supply its self-diagnosis
result to the another sub-module of the multiple sub-modules, and
transmit a self-diagnosis result from the another sub-module of the
multiple sub-modules to the optical receiver.
[0020] Each of the sub-modules may update data and control program
of the another sub-module of the multiple sub-modules.
[0021] According to a second aspect of the present invention, there
is provided an optical amplifying repeater control method of
controlling an optical amplifying repeater in an optical repeating
system including multiple sets of optical transmission lines, an
optical transmitter and an optical receiver for transmitting and
receiving main signals via the multiple sets of optical
transmission lines, and an optical amplifying repeater installed at
an intermediate position on the multiple sets of optical
transmission lines for amplifying and repeating the main signals
with optical amplifiers, the optical amplifying repeater control
method comprising the steps of: transmitting a first sub-signal
containing at least one of a supervisory command and a control
command to the optical amplifying repeater by the optical
transmitter, the supervisory command commanding to supervise
internal circuits of the optical amplifying repeater, and the
control command commanding to control the optical amplifying
repeater; receiving at least one of the supervisory command and the
control command by one of multiple sub-modules in the optical
amplifying repeater via the multiple sets of optical transmission
lines, the multiple sub-modules amplifying and repeating the main
signals on the multiple sets of optical transmission lines; and
transmitting a second sub-signal that contains a supervisory signal
indicating supervisory result corresponding to the supervisory
command from the one of multiple sub-modules to the optical
receiver when the one of multiple sub-modules receives the
supervisory command, and initializing, when the one of multiple
sub-modules receives a predetermined control command, another
sub-module of the multiple sub-modules in response to the
predetermined control command.
[0022] According to a third aspect of the present invention, there
is provided an optical amplifying repeater control method of
controlling an optical amplifying repeater in an optical repeating
system including multiple sets of optical transmission lines, an
optical transmitter and an optical receiver for transmitting and
receiving main signals via the multiple sets of optical
transmission lines, and an optical amplifying repeater installed at
an intermediate position on the multiple sets of optical
transmission lines for amplifying and repeating the main signals
with optical amplifiers, the optical amplifying repeater including
multiple sub-modules each for amplifying and repeating the main
signals on the multiple sets of optical transmission lines, the
optical amplifying repeater control method comprising the steps of:
transmitting a first sub-signal containing at least one of a
supervisory command and a control command from the optical
transmitter to the optical amplifying repeater, the supervisory
command commanding to supervise internal circuits of the optical
amplifying repeater, and the control command commanding to control
the optical amplifying repeater; and transmitting, when one of the
multiple sub-modules receives the supervisory command via the
optical transmission lines, a second sub-signal containing a
supervisory signal indicating supervisory result corresponding to
the supervisory command from the one of the multiple sub-modules to
the optical receiver, and switching, when the one of the
sub-modules receives a predetermined control command via the
optical transmission lines, the optical transmission line for
transmitting the second sub-signal to the transmission line of
another set of the multiple sets of optical transmission lines, via
another sub-module of the multiple sub-modules in response to the
predetermined control command.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] FIG. 1 is a block diagram showing a configuration of an
embodiment 1 of the optical repeating system in accordance with the
present invention;
[0024] FIG. 2 is a block diagram showing a configuration of an
optical amplifier of FIG. 1;
[0025] FIG. 3 is a block diagram showing a configuration of an
optical amplifying repeater of FIG. 1;
[0026] FIG. 4 is a block diagram showing a configuration of a
conventional optical repeating system;
[0027] FIG. 5 is a block diagram showing a configuration of an
optical amplifying repeater of FIG. 4;
[0028] FIG. 6 is a block diagram showing a configuration of the
optical transmitter of FIG. 4; and
[0029] FIG. 7 is a block diagram showing a configuration of the
optical receiver of FIG. 4.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0030] The invention will now be described with reference to the
accompanying drawings.
[0031] FIG. 1 is a block diagram showing a configuration of an
embodiment 1 of the optical repeating system in accordance with the
present invention. In FIG. 1, the reference numeral 601 designates
a line supervisory unit. The line supervisory unit 601 comprises
optical transmitters 611 and optical receivers 612 serving as
terminals of uplink and downlink bidirectional optical transmission
lines, each of which consists of the optical fibers 602-1 and
602-2. The line supervisory unit 601 further comprises a feeding
circuit 613 for supplying current to each optical amplifying
repeater 603 via a feeder line 614. Here, the optical transmitters
611 and optical receivers 612 have the same configuration as those
of FIGS. 6 and 7.
[0032] In FIG. 1, reference numerals 602-1 and 602-2 each designate
an optical fiber constituting the bidirectional optical
transmission line; and 603 designates an optical amplifying
repeater that amplifies main signals on a multiple bidirectional
optical transmission lines, and that comprises a multiple
sub-modules 621 for receiving the first sub-signal and carries out
the processing thereof. In FIG. 1, a pair of the bidirectional
optical transmission lines are installed, where each bidirectional
optical transmission line is defined as an optical fiber pair 604
consisting of the optical fiber 602-1 and optical fiber 602-2.
[0033] In each sub-module 621, the reference numeral 631-1
designates an optical amplifier mounted on the uplink optical
transmission line (optical fiber 602-1) for amplifying the main
signal; 631-2 designates an optical amplifier mounted on the
downlink optical transmission line (optical fiber 602-2) for
amplifying the main signal; and 632 designates a supervisory
controller that transmits, when receiving the supervisory command
addressed to the repeater from the optical transmitter 611 via the
uplink optical transmission line or the downlink optical
transmission line, the supervisory signal indicating the
supervisory result corresponding to the supervisory command to the
optical receivers 612 via the uplink optical transmission line and
downlink optical transmission line as the second sub-signal, and
that controls, when receiving the control command via the uplink
optical transmission line (or the downlink optical transmission
line), the amplification factor of the optical amplifier 631-1
(optical amplifier 631-2) in accordance with the control
command.
[0034] FIG. 2 is a block diagram showing a configuration of the
optical amplifier 631-1 or 631-2 as shown in FIG. 1. In FIG. 2, the
reference numeral 701 designates a coupler for splitting the input
optical signal; 702 designates a WDM (Wavelength Division
Multiplexing) coupler for combining the optical signal with the
pumping laser light; 703 designates an erbium (Er) doped fiber; 704
designates an isolator; and 705 designates a coupler for splitting
the amplified optical signal, and outputting its first part as the
output optical signal. The reference numeral 706 designates a
photoelectric converter for converting the optical signal into an
electrical signal; 707 designates a pumping laser diode for
applying the pumping laser light to the erbium (Er) doped fiber 703
via the WDM coupler 702; and 708 designates a photoelectric
converter for converting the optical signal to an electrical
signal.
[0035] FIG. 3 is a block diagram showing a configuration of the
optical amplifying repeater 603 as shown in FIG. 1. In FIG. 3, the
reference numeral 651 designates a modem unit. The modem unit 651
extracts and demodulates the first sub-signal sent from the optical
transmitter 611 of the line supervisory unit 601. It also modulates
the driving current to the pumping laser diode 707 by the
supervisory signal that includes various items of the
intra-repeater information corresponding to the supervisory
command. It carries out the modulation by controlling the pumping
laser diode drivers 653-1 and 653-2, thereby superimposing the
supervisory signal on the main signal as the second sub-signal. The
reference numeral 652 designates a controller that operates as
follows. When detecting the supervisory command addressed to the
repeater from the first sub-signal, the controller 652 collects the
intra-repeater information, and supplies the modem unit 651 with
the supervisory signal indicating the intra-repeater information.
On the other hand, when detecting the control command addressed to
the repeater from the first sub-signal, it controls the
amplification factors of the pumping laser diode drivers 653-1 and
653-2, thereby controlling the optical amplifiers 631-1 and 631-2.
The reference numeral 661 designates a nonvolatile memory such as
an FRAM (Ferro-electric Random Access Memory) and MRAM
(Magneto-resistive Random Access Memory) for storing the set values
of the amplification factors of the optical amplifiers 631-1 and
631-2, the intra-repeater information and the like. The reference
numeral 653-1 designates the pumping laser diode driver for
supplying the driving current to the pumping laser diode 707 of the
optical amplifier 631-1; and 653-2 designates a pumping laser diode
driver for supplying the driving current to the pumping laser diode
707 of the optical amplifier 631-2.
[0036] The controller 652 can be implemented by a microcomputer
that comprises a ROM (Read Only Memory) for storing the control
program, a RAM serving as a working area and a CPU (Central
Processing Unit). Alternatively, the entire supervisory controller
632 can be implemented by a microcomputer.
[0037] Next, the operation of the present embodiment 1 will be
described.
[0038] The feeding circuits 613 of the line supervisory units 601
at both ends of the optical transmission line feed a current to the
individual optical amplifying repeaters 603 through the feeder line
614.
[0039] Then, the optical transmitter 611 of the line supervisory
unit 601 transmits the main signal to the optical receiver 612 of
the far-end line supervisory unit 601. In addition, when
transmitting a supervisory command or control command to a
specified optical amplifying repeater 603, the optical transmitter
611 superimposes on the main signal the first sub-signal that
contains the address code uniquely assigned to the specified
optical amplifying repeater 603 and the supervisory command or
control command.
[0040] In this case, the optical transmitter 611 modulates a
carrier by the main signal, superimposes the first sub-signal,
converts the resultant electrical signal to the optical signal, and
supplies the optical signal to the optical fiber 602-1 (or
602-2).
[0041] Subsequently, receiving the optical signal via the optical
fiber 602-1 (602-2), the optical amplifying repeater 603 operates
as follows. First, the coupler 701 splits the optical signal, and
supplies a first part of the optical signal to the Er doped optical
fiber 703 via the WDM coupler 702. In this case, the WDM coupler
702 combines the first part of the optical signal with the pumping
laser light fed from the pumping laser diode 707. Then, the optical
signal amplified by the Er doped optical fiber 703 is launched into
the coupler 705 via the isolator 704 to be split by the coupler
705, and a first part of the split optical signal is supplied to
the optical fiber 602-1 (602-2). Thus, the main signal is amplified
and repeated by the optical amplifier 631-1 (631-2) of the optical
amplifying repeater 603.
[0042] On the other hand, a second part of the optical signal split
by the coupler 701 is converted into an electrical signal by the
photoelectric converter 706, and the electrical signal is supplied
to the modem unit 651 of the supervisory controller 632. Likewise,
a second part of the optical signal split by the coupler 705 is
converted into an electrical signal by the photoelectric converter
708, and the electrical signal is supplied to the modem unit 651 of
the supervisory controller 632.
[0043] The modem unit 651 extracts and demodulates only the first
sub-signal from the electrical signal fed from the photoelectric
converter 706, and supplies it to the controller 652. The modem
unit 651 also measures the power level of the output optical signal
from the electrical signal fed from the photoelectric converter
708, and notifies the controller 652 of the power level.
[0044] The controller 652, referring to its uniquely assigned
address code that is stored in the nonvolatile memory 661, makes a
decision as to whether the first sub-signal contains the same
address code as the uniquely assigned address code. When the first
sub-signal contains the same address code as the uniquely assigned
address code, the controller 652 performs the processing
corresponding to the supervisory command or control command
contained in the first sub-signal. On the other hand, when the
first sub-signal does not include the same address code as the
uniquely assigned address code, the controller 652 disregards the
first sub-signal.
[0045] Detecting the supervisory command addressed to the repeater,
the controller 652 collects the intra-repeater information in
response to the supervisory command. The intra-repeater information
includes such information items as the power levels of the input
and output optical signals of the optical amplifying repeater 603,
the amplification factors of the optical amplifiers 631-1 and
631-2, and the driving current level for the pumping laser diode
707. The modulation factors of the second sub-signal are measured
at the optical receiver 612 on receiving such a second sub-signal
exactly as it is that the intra-repeater receives the first
sub-signal by return.
[0046] As the supervisory command, there are a start command for
starting collection of the intra-repeater information, a selection
command for selecting information to be transmitted to the optical
receiver 612 from the intra-repeater information after collecting
the intra-repeater information, and a transmission command for
transmitting the selected information. For example, the optical
transmitter 611 sends the start command, and then the selection
command after a sufficient time period has elapsed to collect the
intra-repeater information, followed by sending the transmission
command. Incidentally, the these commands can be sent at once as a
single command instead of sending them step by step.
[0047] After collecting the intra-repeater information, the,
controller 652 converts the analog values of the information to
digital data, and supplies the data to the modem unit 651. The
modem unit 651 generates the supervisory signal by modulating a
prescribed subcarrier different from the carrier of the main
signal. Then, the modem unit 651 modulates the driving current of
the pumping laser diode 707 in the optical amplifier 631-1 and that
of the pumping laser diode 707 in the optical amplifier 631-2 by
the supervisory signal by controlling the pumping laser diode
drivers 653-1 and 653-2, thereby superimposing the supervisory
signal on both the uplink and downlink main signals as the second
sub-signal. In the course of this, the controller 652 generates the
digital data within a predetermined quantization error, temporarily
stores the data in a memory not shown, and reads the data of the
selected supervisory information from the memory when it detects
the selection command.
[0048] In addition, detecting the control command addressed
thereto, the controller 652 controls the internal circuits in
response to the control command.
[0049] As the control command, there is an alternative sub-module
restart command to restart the control program of the controller
652 of a sub-module 621 different from the sub-module 621 that
receives the initialization command (that is, one of remaining
sub-modules 621 in the optical amplifying repeater), and to
initialize the different sub-module 621.
[0050] Detecting the alternative sub-module restart command, the
controller 652 supplies the controller 652 of the different
sub-module 621 with the restart command to restart the control
program in the controller 652. The microcomputer constituting the
controller 652 usually comprises a reset terminal so that the
microcomputer is restarted when a predetermined signal is applied
to the reset terminal. In this case, the controller 652 applies the
predetermined signal to the reset terminal to restart the
controller 652 of the different sub-module 621.
[0051] The optical receiver 612 in the far-end line supervisory
unit 601 opposing to the line supervisory unit 601 that transmits
the supervisory command receives the optical signal via the optical
fiber 602-1 or 602-2. After converting the optical signal to the
electrical signal, the optical receiver 612 demodulates it to the
main signal and first and second sub-signals. Likewise, the optical
receiver 612 of the line supervisory unit 601 that transmits the
supervisory command receives the second sub-signal via the reverse
direction optical fiber 602-2 or 602-1. The line supervisory unit
601 displays the supervisory information obtained from the second
sub-signal on a display not shown or prints it out by a printer not
shown.
[0052] When the supervisory controller 632 does not receive the
command addressed thereto, it only drives the pumping laser diodes
707 with a reference current without performing the superimposition
of the second sub-signal. Incidentally, the supervision and control
of the optical amplifying repeater 603 can be achieved for
individual sub-modules 621 via the optical transmission line.
[0053] Next, the operation of restarting the supervisory controller
632 of a sub-module 621 will be described when the control program
of the supervisory controller 632 falls into a failure like an
exception.
[0054] In this case, it is difficult for the faulty sub-module 621
to receive the restart command conveyed by the first sub-signal via
the optical transmission line connected to the faulty sub-module
621, and hence to recover the sub-module 621 to the normal
operation. In this state, it is also difficult to acquire the
supervisory information from the sub-module 621. Thus, it is
necessary to restore the normal operation of the sub-module
621.
[0055] Therefore, the line supervisory unit 601 transmits the
alternative sub-module restart command as the first sub-signal to
initialize the faulty sub-module 621 to the alternative sub-module
621 in the optical amplifying repeater 603 where the faulty
sub-module 621 is present via the optical transmission line
connected to the alternative sub-module.
[0056] Receiving the alternative sub-module restart command, the
controller 652 of the supervisory controller 632 of the alternative
sub-module 621 restarts the control program of the controller 652
of the sub-module 621 specified by the alternative sub-module
restart command, thereby placing the operating state of the
sub-module 621 at the initial state. Thus, the operating state of
the sub-module 621 returns to the normal operating state.
[0057] In this way, the faulty sub-module 621 is brought into the
normal state, again.
[0058] Here, the controller 652 of each sub-module 621 executes the
diagnosis of its own supervisory controller 632 in accordance with
its self-diagnostic program, and sends the diagnostic result to the
modem unit 651 of the adjacent sub-module 621. The diagnostic
result is sent to the line supervisory unit 601 so that it can
detect the failure of the sub-module 621 from the diagnostic
result.
[0059] It is also possible to transfer the data and control program
between the sub-modules 621. For example, the controller 652 of the
sub-module 621 can store the data and control program in its own
nonvolatile memory 661, and update their counterparts in the
nonvolatile memory 661 of the controller 652 of the adjacent
sub-module 621. Alternatively, the controller 652 of the sub-module
621 can acquire new data and control program from the line
supervisory unit 601, and update their counterparts stored in the
nonvolatile memory 661 in the controller 652 of the adjacent
sub-module 621 by the new data and control program.
[0060] As described above, the present embodiment 1 is configured
as follows. The optical transmitter 611 transmits the supervisory
command and the control command to the optical amplifying repeater
603 as the first sub-signal, where the supervisory command is to
supervise the internal circuits in the optical amplifying repeater
603, and the control command is to control the optical amplifying
repeater 603. Any one of the multiple sub-modules 621 in the
optical amplifying repeater 603, which amplifies and repeats the
main signals on the multiple sets of the optical transmission
lines, receives the supervisory command and the control command via
the optical transmission line. When the sub-module 621 receives the
supervisory command, it transmits the supervisory signal indicating
the supervisory result associated with the supervisory command to
the optical receiver 612 as the sub-signal. On the other hand, when
the sub-module 621 receives the control command, it initializes the
alternative sub-module 621 in response to the control command. As a
result, the present embodiment 1 offers an advantage of being able
to bring the faulty sub-module 621 into the normal operating state
with ease.
[0061] Embodiment 2
[0062] The present embodiment 2 of the optical repeating system in
accordance with the present invention is configured such that each
sub-module 621 switches when necessary the optical transmission
line for transmitting the second sub-signal to the alternative
optical transmission line in response to the control command via
the alternative sub-module 621.
[0063] Specifically, when there are two pairs of the uplink and
downlink optical transmission lines as shown in FIG. 1, and if one
pair of the optical transmission lines has a failure, the
controller 652 of the supervisory controller 632 in the sub-module
621 of the faulty system controls the modem unit 651 of the
supervisory controller 632 in the sub-module 621 of the faultless
system, so that the second sub-signal is transmitted to the optical
receivers 612 to which the second sub-signal cannot be transmitted
via the faulty system.
[0064] Since the remaining configuration and the operation of the
embodiment 2 of the optical repeating system are the same as those
of the foregoing embodiment 1, the description thereof is omitted
here.
[0065] As described above, the present embodiment 2 is configured
such that it transmits the second sub-signal to the optical
receiver 612 via a pair of the optical transmission lines different
from that through which the first sub-signal is received among a
multiple pairs of the uplink and downlink optical transmission
lines. As a result, the present embodiment 2 offers an advantage of
being able to acquire the supervisory information even if one of
the systems suffers from a failure, thereby improving the
redundancy.
[0066] Although the foregoing embodiments 1 and 2 are described
taking an example where the number of the optical amplifying
repeaters 603 is two, it is obvious that any number of the optical
amplifying repeaters are allowable. Besides, although two
uplink/downlink optical fibers 602-1 and 602-2 are provided, any
number of the optical fibers are applicable.
* * * * *